The present invention relates in general to an automatic washing machine and, more particularly, to an automatic washing machine and a clutching confirmation method thereof wherein a washing and dehydrating tub changes its position between the washing and dehydrating mode positions while ascending and descending in an axial direction of a drive motor by buoyancy and its own weight.
As well known to those skilled in the art, a typical automatic washing machine includes a drive motor and a clutch which are placed at the outside of the lower section of an outer tub and connected to each other by a transmission V-belt. The washing machine also includes a washing shaft and a dehydrating shaft either of which shafts is applied with the rotational force of the drive motor under the clutching operation of the clutch to be rotated, thus to achieve a desired washing operation or a desired dehydrating operation.
With reference to FIG. 1, there is shown an example of the typical automatic washing machine. The washing machine includes a washing and dehydrating tub or an inner tub 12 which is placed in an outer tub 11 such that it is rotated by the rotational force of a drive motor 13.
Here, the drive motor 13 is placed at the outside of the lower section of the outer tub 11 and connected to a clutch assembly 16 by a transmission V-belt 14, which is wrapped about a motor pulley and a clutch pulley, as described above.
The automatic washing machine further includes two types of shafts, that is, a dehydrating shaft 19, which comprises upper and lower dehydrating shafts 19 and 21, and a washing shaft 27. The dehydrating shaft 19 and 21 and the washing shaft 27 coaxially extend from the clutch assembly 16 and are coupled to the inner tub 12 and a rotator 15, respectively. Here, the rotator 15 will be a pulsator or an agitator in accordance with the type of the washing machine.
FIG. 2 is an enlarged sectional view showing a construction of the clutch assembly 16. In this clutch assembly 16, a spring block 18 is fixed to a lower section of a gear shaft 17 and directly applied with the rotational force of the drive motor 13 through the V-belt 14.
A clutch spring 22 is mounted about the lower dehydrating shaft 21 which is integrally formed with both the upper dehydrating shaft 19 and a brake drum and gear housing 20. This clutch spring 22 controls the rotational force of the drive motor 13 transmitted to the clutch assembly 16 during the washing operation of the washing machine.
In order to apply a predetermined pressure to the outer surface of the brake drum and gear housing 20, a brake band 29 is wrapped about the brake drum and gear housing 20.
The clutch assembly 16 also includes a clutch boss 23 which is provided with teeth 23a at its circumferential surface and coupled to the outer surface of the clutch spring 22. In addition, a clutch boss cam 25 is rotatably mounted on a lower end of a brake lever 24.
The brake lever 24 is placed at a predetermined position where it is engaged with the teeth 23a of the clutch boss 23 and cooperates with a drain valve operating solenoid (not shown) which is mounted on a side of the outer tub 11.
In order to prevent reverse rotation of the inner tub 12, the clutch assembly 16 includes an one way spring clutch 26.
A planet gear 28 is provided in the clutch assembly 16 for reduction of the rotational force of the gear shaft 17 prior to transmission of this rotational force to the washing shaft 27.
In the case of the washing mode of this typical automatic washing machine, the clutch is in a non-clutched state, so that only the rotator 15 is alternately rotated in opposed directions while the-inner tub 12 is stopped. However, in the case of the dehydrating mode of the washing machine, the clutch is in a clutched state, so that the rotator 15 and the inner tub 12 are simultaneously rotated at the same high rotational speed.
Hereinbelow, the operations of the typical washing machine in the washing mode and dehydrating mode will be described in detail.
In the washing mode of the washing machine, the forward rotational force of the drive motor 13 is transmitted to the clutch assembly 16 through the V-belt 14 wrapped about the clutch pulley. In this case, the clutch pulley is rotated in the forward direction and this forward rotation of the pulley makes the clutch spring 22 be tightened, thus to transmit the rotational force of the drive motor 13 to the lower dehydrating shaft 21 through the spring block 18.
However, the teeth 23a of the clutch boss 23 on the outer surface of the clutch spring 22 push the clutch boss cam 25 and prevent tightening of the clutch spring 22, thereby causing no rotational force of the motor 13 to be transmitted to the upper dehydrating shaft 19.
At this time, the rotational force of the motor transmitted to the gear shaft 17 is reduced by the planet gear 28 and, thereafter, transmitted only to the washing shaft 27.
Only the rotator 15 coupled to the washing shaft 27 is thus rotated in order to achieve the desired washing operation.
Meanwhile, the reverse rotational force of the drive motor 13 in the washing mode is transmitted to the clutch assembly 16 through the V-belt 14 in the same manner as described for the above forward rotational force. In this case, the clutch pulley is rotated in the reverse direction and this makes the clutch spring 22 be loosened, thus to cause the rotational force of the gear shaft 17 not to be transmitted to the dehydrating shaft 19 but to washing shaft 27 through the planet gear 28. At this time, the rotational force is reduced by the planet gear 28 prior to its transmission to the washing shaft 27.
When the rotational force of the gear shaft 17 is reduced by the planet gear 28, there is generated a reaction torque in the gear housing 20, so that the upper dehydrating shaft 19 may be rotated in reverse direction.
However, this reverse rotation of the dehydrating shaft 19 is reliably prevented by both the one way spring clutch 26 and the brake band 29 wrapped about the brake drum and gear housing 20.
In the dehydrating mode of the washing machine, the forward rotational force of the drive motor 13 is transmitted to the clutch assembly 16 through the V-belt 14 wrapped about the clutch pulley. In this case, the clutch pulley is rotated in the forward direction and this forward rotation of the pulley makes the clutch spring 22 be tightened, thus to turn on the drain valve operating solenoid (not shown) and to pull a lever 30.
The clutch spring 22 thus comes into close contact with the spring block 18, and the clutch boss cam 25 of the brake lever 24 cooperating with the lever 30 is separated from the teeth 23a of the clutch boss 23 and, at the same time, the brake band 29 is released from the outer surface of the gear housing 20. Therefore, the rotational force of the spring block 18 is transmitted to the lower dehydrating shaft 21 of the gear housing 20 and rotates the upper dehydrating shaft 19, integrally formed with the gear housing 20, at a high speed without speed reduction. The inner tub 12 and the rotator 15, which are coupled to the dehydrating shaft 19 and the washing shaft 27 respectively, are thus rotated at the high speed, thereby achieving the desired dehydrating operation.
When the desired dehydration is finished or the dehydration mode of the washing machine is canceled, the drain valve operating solenoid is turned off.
Upon turning off the drain valve operating solenoid, the pulled lever 30 is released from its pulled state, and the clutch boss cam 25 is engaged with the teeth 23a of the clutch boss 23. At the same time, the brake band 29 is tightened on the outer surface of the gear housing 20, thus to cause the washing machine to be converted in its mode into the washing mode. The rotation of the brake drum and gear housing 20 is thus stopped.
Accordingly, the inner tub 12 coupled to the dehydrating shaft 19 and to the gear housing 20 is stopped in order to end the operation of the washing machine.
As described above, the typical automatic washing machine should have a complex clutch assembly for selective transmission of the rotational force of the drive motor to the inner tub in accordance with the operational mode of the washing machine. Hence, the washing machine is apt to be broken down in parts of its complex clutch. In addition, the provision of the clutch assembly causes generation of vibration and power loss in selective transmission of the rotational force of the drive motor to the washing shaft or to the dehydrating shaft.